To date, the most frequently used sensors for confocal microscopy are photoelectron multiplier tubes (PMT) that offer low-noise electrical signals over a large range of illumination intensities. The main disadvantage of PMTs is the comparably low quantum efficiency of ~30 % – in the best case, for classical photocathodes and not exceeding 45 % for
Gates Open for Improved Confocal Fluorescence and Super-Resolution STED
True confocal microscope systems feature single-point illumination and single-point detection . The method is called "optical sectioning" since the generated image contains only information from the focal plane. The serial detection offers highly efficient and low-noise sensors for signal conversion. Although the nonparallel detection is not conducive to high-speed imaging, modern scanning concepts allow frame rates above 400 frames per second at reasonable noise levels. This is by far enough for most applications, including the monitoring of fast ion-transport phenomena in living material.